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Liquid Handling

Yuezhi He, Kai Liu, Corinna Au, Qiushuo Sun, Edward P J Parrott, Emma Pickwell-MacPherson
A key step to transform terahertz imaging to a practical medical imaging modality lies in the understanding the interactions between terahertz (THz) waves and biological tissues. Most of the models in the literature use the permittivity of liquid water to simulate the THz-tissue interactions but they often neglect the contributions from biological background such as proteins and lipids as dehydrated biological samples are experimentally difficult to prepare. In this work, we present a method to prepare thin and flat dehydrated samples which can be easily handled and measured in a transmission setup...
September 25, 2017: Physics in Medicine and Biology
Anna M Elert, Roland Becker, Erik Duemichen, Paul Eisentraut, Jana Falkenhagen, Heinz Sturm, Ulrike Braun
In recent years, an increasing trend towards investigating and monitoring the contamination of the environment by microplastics (MP) (plastic pieces < 5 mm) has been observed worldwide. Nonetheless, a reliable methodology that would facilitate and automate the monitoring of MP is still lacking. With the goal of selecting practical and standardized methods, and considering the challenges in microplastics detection, we present here a critical evaluation of two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction with subsequent size exclusion chromatography (SEC) using a soil with known contents of PE, PP, PS and PET as reference material...
September 20, 2017: Environmental Pollution
L Detemmerman, S Olivier, V Bours, F Boemer
OBJECTIVES: Hemoglobin (Hb) disorders consist of thalassemia and Hb structural variants, of which the major forms are associated with severe anemia and/or vascular occlusion. Current diagnostic techniques are highly accurate and mostly based on isoelectric focusing, high-performance liquid chromatography or mass spectrometry, which often require advanced laboratory equipment. In sub-Saharan Africa, the Hb disorders are mainly associated to the pathological variants hemoglobin S (HbS) and HbC...
September 20, 2017: Hematology (Amsterdam, Netherlands)
Pablo Jiménez-Bonilla, Yi Wang
Butanol is a precursor of many industrial chemicals, and a fuel that is more energetic, safer and easier to handle than ethanol. Fermentative biobutanol can be produced using renewable carbon sources such as agro-industrial residues and lignocellulosic biomass. Solventogenic clostridia are known as the most preeminent biobutanol producers. However, until now, solvent production through the fermentative routes is still not economically competitive compared to the petrochemical approaches, because the butanol is toxic to their own producer bacteria, and thus, the production capability is limited by the butanol tolerance of producing cells...
September 18, 2017: Critical Reviews in Biotechnology
Matthew W Turner, John R Cort, Owen M McDougal
Nine publically available biosafety protocols for safely handling conotoxin peptides were tested to evaluate their decontamination efficacy. Circular dichroism (CD) spectroscopy and mass spectrometry (MS) were used to assess the effect of each chemical treatment on the secondary and primary structure of α-CTx MII (L10V, E11A). Of the nine decontamination methods tested, treatment with 1% (m/v) solution of the enzymatic detergent Contrex™ EZ resulted in a 76.8% decrease in α-helical content as assessed by the mean residue ellipticity at 222 nm, and partial peptide digestion was demonstrated using high performance liquid chromatography mass spectrometry (HPLC-MS)...
September 14, 2017: Toxins
Gabriel Germán Siano, Milagros Montemurro, Mirta Raquel Alcaráz, Hector Casimiro Goicoechea
In the current analytical chemistry, even though the modeling of higher-order data can result attractive, the generation of this kind of data implies some automation challenges, which are mainly related to the hidden programming languages and electronic details of the equipment. When techniques and/or equipment hyphenation is the key to obtain higher-order data, the required simultaneous control of them demands funds for new hardware, software and licenses, and also really skilled operators. In this work we present Design of Inputs-Outputs with Sikuli (D...
September 13, 2017: Analytical Chemistry
Daniel C Joaquim, Eduardo D Borges, Iara G R Viana, Paula A Navarro, Alessandra A Vireque
The introduction and widespread application of vitrification are one of the most important achievements in human assisted reproduction techniques (ART) of the past decade despite controversy and unclarified issues, mostly related to concerns about disease transmission. Guidance documents published by US Food and Drug Administration, which focused on the safety of tissue/organ donations during Zika virus spread in 2016, as well as some reports of virus, bacteria, and fungi survival to cryogenic temperatures, highlighted the need for a review of the way how potentially infectious material is handled and stored in ART-related procedures...
2017: BioMed Research International
M Roozbahani, M Alehosseini, M Kharaziha, R Emadi
This study aimed to develop nano‑calcium phosphate cement (nCPC) and evaluate the effect of nanosized precursors on mechanical, physical and handling properties (injectability and setting time) as well as conversion rate of nano-reactants into nano-hydroxyapatite (nHA). In this study, while alpha tricalcium phosphate (α-TCP, 98wt%) and HA (2wt%) were applied as the powder phase, 2.5wt% NaH2PO4 solution was used as liquid phase of cement. Before nano-CPC preparation, Si-stabilized α-TCP nanopowder with particle size of 10±3...
December 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Shi-Ping Zhao, Yan Ma, Qi Lou, Hong Zhu, Bo Yang, Qun Fang
Three-dimensional (3D) cell culture provides an effective way over conventional two-dimensional (2D) monolayer culture to more closely imitate the complex cellular organization, heterogeneity, and interactions as well as tissue microenvironments in vivo. Here we present a novel droplet-based 3D cell culture method by using droplet array attached on the sidewall of a PDMS piece. Such an arrangement not only avoids cells from adhering on the chip surface for achieving 3D cell culture in nanoliter-scale droplets, but also facilitates performing multiple operations to cells in droplets, including cell suspension droplet generation, drug treatment, and cell staining with a capillary-based liquid handling system, as well as in situ observation and direct scanning with a confocal laser scanning microscope...
September 21, 2017: Analytical Chemistry
Ganesh M Shankar, Leonora Balaj, Shannon L Stott, Brian Nahed, Bob S Carter
Minimally invasive methods will augment the clinical approach for establishing the diagnosis or monitoring treatment response of central nervous system tumors. Liquid biopsy by blood or cerebrospinal fluid sampling holds promise in this regard. Areas covered: In this literature review, the authors highlight recent studies describing the analysis of circulating tumor cells, cell free nucleic acids, and extracellular vesicles as strategies to accomplish liquid biopsy in glioblastoma and metastatic tumors. The authors then discuss the continued efforts to improve signal detection, standardize the liquid biopsy handling and preparation, develop platforms for clinical application, and establish a role for liquid biopsies in personalized medicine...
September 6, 2017: Expert Review of Molecular Diagnostics
Chuxin Li, Lei Wu, Cunlong Yu, Zhichao Dong, Lei Jiang
Separation of water-in-oil droplet is important in environmental protections, bioassays, and saving functional inks. So far, bulk oil-water separation has been achieved by membrane separation and sponge absorption, but micro-drop separation still remains a challenge. Here we report that instead of the "plug and go" separation model, tiny water-in-oil droplets can be separated into pure water and oil droplets through "go in opposite ways" on the curved peristome-mimetic surfaces in milliseconds without energy input...
September 5, 2017: Angewandte Chemie
Dan Luo, Tingting Deng, Wei Yuan, Hui Deng, Ming Jin
BACKGROUND: Age-related macular degeneration (AMD) is a leading disease associated with blindness. It has a high incidence and complex pathogenesis. We aimed to study the metabolomic characteristics in Chinese patients with wet AMD by analyzing the morning plasma of 20 healthy controls and 20 wet AMD patients for metabolic differences. METHODS: We used ultra-high-pressure liquid chromatography and quadrupole-time-of-flight mass spectrometry for this analysis. The relationship of these differences with AMD pathophysiology was also assessed...
September 6, 2017: BMC Ophthalmology
Cheng-Ying Wu, Ming Kong, Wei Zhang, Fang Long, Jing Zhou, Shan-Shan Zhou, Jin-Di Xu, Jun Xu, Song-Lin Li
Ginger (Zingiberis Rhizoma), a commonly-consumed food supplement, is often sulphur-fumigated during post-harvest handling, but it remains unknown if sulphur fumigation induces chemical transformations in ginger. In this study, the effects of sulphur fumigation on ginger chemicals were investigated by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS)-based metabolomics. The results showed that sulphur fumigation significantly altered the holistic chemical profile of ginger by triggering chemical transformations of certain original components...
January 15, 2018: Food Chemistry
Huiyan Li, Robert Popp, Bjorn Frohlich, Michael X Chen, Christoph H Borchers
Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a result of the direct detection of the mass-to-charge ratio of each target molecule. However, MS-based proteomics, like most other analytical techniques, has a bias towards measuring high-abundance analytes, so it is challenging to achieve detection limits of low ng/mL or pg/mL in complex samples, and this is the concentration range for many disease-relevant proteins in biofluids such as human plasma...
August 18, 2017: Journal of Visualized Experiments: JoVE
Yingzhi Hu, Huaidong Peng, Youshao Yan, Shuyu Guan, Shumei Wang, Paul C H Li, Yue Sun
The design, construction and testing for integration of liquid-liquid extraction (EX) and capillary electrophoretic (CE) separation on one glass microchip was reported. In this EX-CE chip, a 1.5 cm-long and 200 μm-wide EX channel was used for extraction based on the two-phase laminar flow, followed by a single-cross CE unit for on-line analysis without any auxiliary devices. One side of the EX channel surface for the organic solvent phase was selectively modified to be hydrophobic while the surface of the other side for the aqueous phase remained hydrophilic, and the extraction product reservoir is also used as the sample reservoir for the subsequent chip separation in the CE channel...
September 8, 2017: Analytica Chimica Acta
T S Kaminski, P Garstecki
Droplet microfluidics is a relatively new and rapidly evolving field of science focused on studying the hydrodynamics and properties of biphasic flows at the microscale, and on the development of systems for practical applications in chemistry, biology and materials science. Microdroplets present several unique characteristics of interest to a broader research community. The main distinguishing features include (i) large numbers of isolated compartments of tiny volumes that are ideal for single cell or single molecule assays, (ii) rapid mixing and negligible thermal inertia that all provide excellent control over reaction conditions, and (iii) the presence of two immiscible liquids and the interface between them that enables new or exotic processes (the synthesis of new functional materials and structures that are otherwise difficult to obtain, studies of the functions and properties of lipid and polymer membranes and execution of reactions at liquid-liquid interfaces)...
August 31, 2017: Chemical Society Reviews
Robert Popp, Huiyan Li, André LeBlanc, Yassene Mohammed, Adriana Aguilar-Mahecha, Andrew G Chambers, Cathy Lan, Oliver Poetz, Mark Basik, Gerald Batist, Christoph H Borchers
The PI3K/AKT/mTOR pathway is one of the most commonly dysregulated signaling pathways that is linked to cancer development and progression, and its quantitative protein analysis holds the promise to facilitate patient stratification for targeted therapies. Whereas immunohistochemistry (IHC) and immunoassays are routinely used for clinical analysis of signaling pathways, mass spectrometry-based approaches such as liquid chromatography electrospray ionization-multiple reaction monitoring (LC/ESI-MRM) are more commonly used in clinical research...
August 30, 2017: Analytical Chemistry
Xiaofei Liu, Changning Guo, Badrul Chowdhury, Peter Starke, Susan Limb, Prasad Peri, Alan Schroeder, William Doub
BACKGROUND: Multiple factors may influence the performance of a metered dose inhaler (MDI) when used with a valved holding chamber (VHC or "spacer"). METHODS: Andersen Cascade Impactor measurements were conducted for three MDI products and two different VHCs using a specially designed system that accommodated variable delay times between MDI actuation and introduction of the aerosol into the impactor, and allowed reduced flow through the VHC while the impactor was operated at 28...
August 28, 2017: Journal of Aerosol Medicine and Pulmonary Drug Delivery
Kyle L Hogan, Danielle Leiske, Cleo M Salisbury
N-Acetyl-tryptophan (NAT) is used as a stabilizer for preparations of human serum albumin and has more recently been demonstrated to provide oxidative protection for labile Trp residues in monoclonal antibodies. As a component in the formulations of protein therapeutics, NAT is sacrificially degraded; therefore understanding the identity and quantity of NAT degradants potentially formed in these drug products is essential to understanding the potential patient impact of this additive. Here we report a simple reversed phase chromatography approach that allows systematic investigation of NAT degradation in relevant formulations under stressed conditions...
August 24, 2017: Journal of Pharmaceutical Sciences
Fariborz Bahrehmand, Amir Kiani, Asad Vaisi-Raygani, Homayoun Bashiri, Mehdi Zobeiri, Ali Moini, Tayebeh Pourmotabbed
Thiopurine drugs remain pivotal therapies for the wide varieties of diseases such as inflammatory bowel disease (IBD). Here, thiopurine S-methyltransferase (TPMT) phenotype, the main metabolizing enzyme of thiopurine-drugs, was studied. This is for the first time that TPMT activity is measured in Iranian IBD patients. We used an improved direct liquid chromatography assay without need for solvent extraction and minimize excess labor handling making it ideal for use in routine referral medical centers. TPMT activity in whole blood was determined by a non-extraction HPLC method...
June 2017: Acta Medica Iranica
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